System and method for searching applications using multimedia content elements

ABSTRACT

A method and system for searching for mobile applications using a multimedia content element are provided. The system comprises receiving an input search query including the multimedia content element; generating at least one signature for the at least one multimedia content element; generating a textual query using at least the one generated signature; querying at least one application distribution platform using the generated textual search query; analyzing search results returned responsive to the textual query to determine relevancy of mobile applications designated in the search results to the multimedia content element; and causing the display of mobile applications on a user device submitting the input search query.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/781,847 filed on Mar. 14, 2013, the contents of which are hereby incorporated by reference. This application is a continuation-in-part (CIP) of U.S. Patent Application No. 13/773,112 filed on Feb. 21, 2013, now pending, which is a CIP of:

-   -   (a) U.S. patent application Ser. No. 13/344,400 filed on Jan. 5,         2012, now pending, which is a continuation of U.S. patent         application Ser. No. 12/434,221, filed May 1, 2009, now U.S.         Pat. No. 8,112,376;     -   (b) U.S. patent application Ser. No. 13/682,132 filed Nov. 20,         2012, which is a continuation application of U.S. patent         application Ser. No. 12/195,863, filed Aug. 21, 2008, now U.S.         Pat. No. 8,326,775. The 12/195,863 application claims priority         under 35 USC 119 from Israeli Application No. 185414, filed on         Aug. 21, 2007, and is also a continuation-in-part of the         below-referenced U.S. patent application Ser. No. 12/084,150;         and,     -   (c) U.S. patent application Ser. No. 12/084,150 having a 371         filing date of Apr. 7, 2009, now U.S. Pat. No. 8,655,801, which         is the National Stage of International Application No.         PCT/IL2006/001235, filed on Oct. 26, 2006, which claims foreign         priority from Israeli Application No. 171577 filed on Oct. 26,         2005 and Israeli Application No. 173409 filed on 29 Jan. 2006.

All of the applications referenced above are herein incorporated by reference for all that they contain.

TECHNICAL FIELD

The present invention relates generally to the analysis of multimedia content elements, and more specifically for searching techniques utilizing multimedia content elements for searching of applications.

BACKGROUND

Software applications, such as mobile applications (or apps) are designed for execution over mobile devices (typically a smart phone or tablet computer). Such apps, referred to hereinafter as “mobile apps”, are usually available through application distribution platforms and can be downloaded from such platforms or repositories, for example, AppStore®, GooglePlay®, Windows® Phone play, and the like.

Hundreds of thousands of mobile applications are currently available in the various application distribution platforms. Several search tools that are currently provided by the distribution platforms or as external tools are designed to assist a user to find a specific application. The search tools may include, for example, a textual-based search engine, classification engines, and recommendation engines. A classification engine typically classifies applications, based on popularity, cost, category (e.g., games, travel, etc.).

The explosion in the number of available mobile applications, and the different combinations of types of applications, makes it increasingly difficult for users to search for a mobile application relevant to their specific interests. In most cases, in order to find relevant mobile applications, a well-defined search term is required and/or prior knowledge of the applications' classification is required. However, for novice users it may be difficult to express their desired results in words. Alternatively, users would have to browse through hundreds of applications if they do not provide a descriptive search term or search by a category.

It would be therefore advantageous to provide an efficient and intuitive solution for searching for mobile applications in application distribution platforms.

SUMMARY

Certain embodiments include herein include a system and method for searching for mobile applications using a multimedia content element. The method comprises receiving an input search query including the multimedia content element; generating at least one signature for the at least one multimedia content element; generating a textual query using at least the one generated signature; querying at least one application distribution platform using the generated textual search query; analyzing search results returned responsive to the textual query to determine relevancy of mobile applications designated in the search results to the multimedia content element; and causing the display of mobile applications on a user device submitting the input search query.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter disclosed herein is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 is a schematic block diagram of a network system utilized to describe the various embodiments disclosed herein.

FIG. 2 is a flowchart describing a method for searching for relevant mobile applications using multimedia content elements according to an embodiment.

FIG. 3 is a block diagram depicting the basic flow of information in the signature generator system.

FIG. 4 is a diagram showing the flow of patches generation, response vector generation, and signature generation in a large-scale speech-to-text system.

DETAILED DESCRIPTION

It is important to note that the embodiments disclosed herein are only examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily limit any of the various claimed inventions. Moreover, some statements may apply to some inventive features but not to others. In general, unless otherwise indicated, singular elements may be in plural and vice versa with no loss of generality. In the drawings, like numerals refer to like parts through several views.

FIG. 1 shows an exemplary and non-limiting schematic diagram of a system 100 for processing multimedia content displayed on a user device according to an embodiment. A network 110 is used to communicate between different parts of the system. The network 110 may be the Internet, the world-wide-web (WWW), a local area network (LAN), a wide area network (WAN), a metro area network (MAN), and

CORT 4259 other networks for enabling communication between the elements of the system 100. Further connected to the network 110 are one or more user devices (Ud) 120-1 through 120-n (collectively referred to hereinafter as user devices 120 or individually as a user device 120, merely for simplicity purposes). A user device 120 may be, for example, a mobile phone, a smart phone, a tablet computer, a wearable computing device, a personal computer, and other kinds of wired and mobile appliances, equipped with browsing, viewing, listening, capturing and managing capabilities, etc., that are enabled as further discussed herein below.

A server 130 is further connected to the network 110. The system 100 also includes a signature generator system (SGS) 140. In one embodiment, the SGS 140 is connected either directly or through the network 110 to the server 130. In another embodiment, the SGS 140 is a component integrated in the server 130. The server 130 is configured to receive and serve multimedia content elements and causes the SGS 140 to generate a signature respective of the multimedia content elements. The process for generating the signatures for multimedia content elements, is explained in more detail herein below with respect to FIGS. 3 and 4.

The various elements of the system 100 as depicted in FIG. 1 are also described in a co-pending U.S. patent application Ser. No. 13/344,400 (hereinafter the '400 Application) to Raichelgauz, et al., which is assigned to common assignee, and is hereby incorporated by reference for all that it contains.

A plurality of application distribution platforms 150-1 through 150-m are also connected to the network 110. Application distribution platforms 150 may provide a repository for mobile applications, through which users can download mobile applications to the user devices 120. An application distribution platform 150 may maintain an index of mobile applications, each entry in index may link to a repository hosting the indexed mobile application. Non-limiting examples for the application distribution platforms include AppStore®, GooglePlay®, Windows® phone store, and the like.

According to the disclosed embodiments, the server 130 in conjunction with the SGS 140, is configured to determine which mobile applications are most relevant to a user device 120 based on an input search query that includes a multimedia content element. In an embodiment, such a content element may be viewed or captured by the user device 120. As a non-limiting example, the received multimedia content element may be an icon of a mobile application, a picture taken by the user, an image included in a web site, and the like. The multimedia content element can be sent by a script executed, for example, in a web browser (not shown) in the device 120, an add-on (not shown) installed in the web browser, or a mobile application installed in the device 120 and configured to communicate with the server 130.

Upon reception of the input query, the server 130 by means of the SGS 140 is configured to generate at least one signature. In one embodiment, by using the at least one signature generated for the content element at least a textual query is generated. Specifically, in one embodiment, the generated signature(s) are utilized to query a database of concepts to detect at least one concept that matches the signatures. The metadata of the at least one matching concept can be utilized as the textual query.

A concept is a collection of signatures representing elements of the unstructured data and metadata describing the concept. As a non-limiting example, a ‘Superman concept’ is a signature reduced cluster of signatures describing elements (such as multimedia content elements) related to, e.g., a Superman cartoon: a set of metadata representing textual representation of the Superman concept. Techniques for generating concepts and concept structures are also described in U.S. Pat. No. 8,266,185 to Raichelgauz, et al., which is assigned to common assignee, and is incorporated hereby by reference for all that it contains.

An exemplary database of concepts is disclosed in a co-pending U.S. patent application No. 13/766,463, filed Feb. 13, 2013, entitled “A SYSTEM AND METHODS FOR GENERATION OF A CONCEPT BASED DATABASE”, assigned to common assignee, and is hereby incorporated by reference for all the useful information it contains.

In another embodiment, the generated signatures are analyzed by the server 130 to determinate a context of the multimedia content element. The textual query is generated respective of the determined context. A context is determined as the correlation between a plurality of concepts. An example for such indexing techniques using signatures is disclosed in a co-pending U.S. patent application Ser. No. 13/766,463, referenced above.

An exemplary technique for determining a context of a multimedia content element based on the generated signatures is described in detail in U.S. patent application Ser. No. 13/770,603, filed on Feb. 19, 2013, assigned to common assignee, which is hereby incorporated by reference for all the useful information it contains. According to one embodiment, the analysis enables the generation of a textual query to be used through the search engines of the web sources 150.

In yet another embodiment, in order to generate a textual search query, the signature provided by the SGS 140 is checked against a query database (not shown) that maintains mappings between a signature's textual queries. That is, the query database maintains for each signature a matching textual query. It should be noted that different signatures can be mapped to the same query. For example, a picture of a car make BMW and model X3 can be taken from different angles, or the same type of car can be presented in different colors. In the query database accessed by the server 130, signatures of images of a car make BMW and model X3 are mapped to one text query, for example, “BMW X3 model.”

The textual query is sent to one or more of the application distribution platforms 150. In an embodiment, the textual query is sent only to platforms with mobile applications that can be downloaded to the user device 120 providing the input query. As an example, if the user device 120 runs iOS® operating system, then the AppStore® is queried with the generated textual query. The search typically returns icon images (hereinafter “icons”) representing mobile applications that match the textual query. In some cases, an icon may be achieved with one or more screenshots and/or a text description of the respective mobile application.

In an embodiment, the search results are analyzed to determine the relevancy of each mobile application (designated in the results) to the input query. With this aim, signatures are generated, by means of the SGS 140, to an icon, screenshots, and/or a text description of each mobile application returned by the platform 150. The generated signatures may be clustered. Then, the server 130 is configured to match the generated signatures or their cluster to the at least one signature generated for the multimedia content element included in the search query. Signatures that overlap more than a predetermined threshold level, for example 60%, are considered as matching signatures. Thus, search results in which the signatures match the input content element's signatures are considered relevant to the user submitting the input query. According to various exemplary embodiments, the relevancy of mobile applications may be determined based on contextual relativity of the icon to the multimedia content element and/or user's interests.

Mobile applications included in the search results that are determined to be relevant are returned and displayed over the user device 120 providing the input query. Additionally, relevant mobile applications and the respective multimedia content element and generated textual query are stored in a data warehouse 160 for further use by the server 130, for example, to provide association of mobile applications with multimedia content elements.

FIG. 2 is an exemplary and non-limiting flowchart 200 describing a method for searching for relevant mobile applications using multimedia content elements according to an embodiment.

In S210, an input query including at least a multimedia content element or portions thereof is received. The input query includes a request to search for mobile applications matching the request. In an embodiment, the input query is sent from a user device 120. The input query may include, for example, an image, a graphic, a video stream, a video clip, an audio stream, an audio clip, a video frame, a photograph, and an image of signals (e.g., spectrograms, phasograms, scalograms, etc.), and/or combinations thereof and portions thereof.

According to one embodiment, the input query may include additional parameters to enhance the search operation. The additional parameters are received, for example, through an overlay object created by the server 130 over the multimedia content element. The overlay may include a search box or other interactive object. The additional parameters, provided as part of the search request, may be, for example, a specific portion within the multimedia content element or other conditions respective thereto. Optionally, S210 may also include receiving demographic information and/or location information related to the user submitting the query.

In S220, at least one signature respective of the input multimedia content element is generated. The signature for the multimedia content element is generated by the SGS 140 as described below. As noted above, the generated signature may be robust to noise and distortions. A signature can be generated for each portion identified in the input multimedia content element.

In S230, a textual query is generated based on the at least one signature. In one embodiment, S230 includes querying a database of concepts to detect at least one concept that matches the signatures. The metadata of the matching concepts can be utilized as the textual query. A matched concept is a concept in which its signature and the generated signatures overlap more than a predetermined threshold level, for example 60% of the signatures match. Such signatures may be considered as matching.

In another embodiment, S230 includes determining, using the generated signatures, a context for the multimedia content element and/or the portions of a particular interest to determine the textual query. A context is a correlation between a plurality of concepts, thus the correlated metadata of the context (i.e., its concepts) can be utilized as the textual query.

In yet another embodiment, S230 includes searching a query database for a textual query that matches one or more of the generated signatures. The query database maintains mappings of signatures to textual queries.

In an embodiment, the generated textual query may be further optimized using an input parameter, behavior and/or demographic information provided in the input query at S210.

In S240, the generated textual query is fed to at least one application distribution platform 150 to search for potential applications. In an embodiment, only application distribution platforms that contain mobile applications that can be downloaded and installed on the user device 120 submitting the input query are queried.

The search results returned by the at least one application distribution platform may include, for each mobile application, matching the textual query to at least an icon, one or more screenshots, and a description of the mobile application.

In S250, the search results are analyzed in order to determine their relevancy to the input query, and in particular to the multimedia content element. In an embodiment, signatures are generated, by means of the SGS 140, to an icon, screenshots, and/or text description of each mobile application returned by the at least one platform 150. The generated signatures may be clustered. Then, the generated signatures or their clusters are matched against the at least one signature generated for the multimedia content element included in the search query. Signatures that overlap more than a predetermined threshold level, for example 60%, are considered as matching signatures. Thus, search results in which the signatures match the input content element's signatures are considered relevant to the user submitting the input query. According to various exemplary embodiments, S250 further includes determining the relevancy of mobile applications based on contextual relativity of the icon to the multimedia content element and/or user's interests.

In S260, the mobile applications determined to be relevant are displayed on the user device 120 submitting the input query. In S270 it is checked whether additional input queries need to be served, and if so, execution continues with S210; otherwise, execution terminates.

In an embodiment, the method discussed in FIG. 2 is performed by the server 130. In another embodiment, the method can be adapted to allow the generation of textual queries by a user device, for example, the user device 120.

Following is a non-limiting example for operation of the method described in FIG. 2. The server 130 receives an image of a traffic sign in Chinese language. The image is then analyzed and a plurality of signatures is generated respective thereto. The textual query generated may be, for example, “Chinese dictionary.” Several applications are then received respective of the generated query. The icons representing the application as well as the description of the applications are then analyzed. The analysis shows that several of the applications received allow translation of English to Chinese while others allow translation of Chinese to English.

As the multimedia content element shows a traffic sign in Chinese, only mobile applications that allow Chinese to English translation are determined to be relevant to the input query.

FIGS. 3 and 4 illustrate the generation of signatures for the multimedia content elements by the SGS 140 according to one embodiment. An exemplary high-level description of the process for large scale matching is depicted in FIG. 3. In this example, the matching is for a video content.

Video content segments 2 from a Master database (DB) 6 and a Target DB 1 are processed in parallel by a large number of independent computational Cores 3 that constitute an architecture for generating the Signatures (hereinafter the “Architecture”). Further details on the computational Cores generation are provided below. The independent Cores 3 generate a database of Robust Signatures and Signatures 4 for Target content-segments 5 and a database of Robust Signatures and Signatures 7 for Master content-segments 8. An exemplary and non-limiting process of signature generation for an audio component is shown in detail in FIG. 4. Finally, Target Robust Signatures and/or Signatures are effectively matched, by a matching algorithm 9, to Master Robust Signatures and/or Signatures database to find all matches between the two databases.

To demonstrate an example of signature generation process, it is assumed, merely for the sake of simplicity and without limitation on the generality of the disclosed embodiments, that the signatures are based on a single frame, leading to certain simplification of the computational cores generation. The Matching System is extensible for signatures generation capturing the dynamics in-between the frames.

The Signatures' generation process will now be described with reference to FIG. 4. The first step in the process of signatures generation from a given speech-segment is to breakdown the speech-segment to K patches 14 of random length P and random position within the speech segment 12. The breakdown is performed by the patch generator component 21. The value of the number of patches K, random length P and random position parameters is determined based on optimization, considering the tradeoff between accuracy rate and the number of fast matches required in the flow process of the server 130 and SGS 140. Thereafter, all the K patches are injected in parallel into all computational Cores 3 to generate K response vectors 22, which are fed into a signature generator system 23 to produce a database of Robust Signatures and Signatures 4.

In order to generate Robust Signatures, i.e., Signatures that are robust to additive noise L (where L is an integer equal to or greater than 1) by the Computational Cores 3 a frame ‘i’ is injected into all the Cores 3. Then, Cores 3 generate two binary response vectors: {right arrow over (S)} which is a Signature vector, and {right arrow over (RS)} which is a Robust Signature vector.

For generation of signatures robust to additive noise, such as White-Gaussian-Noise, scratch, etc., but not robust to distortions, such as crop, shift and rotation, etc., a core C_(i)={n_(i)} (1≦i≦L) may consist of a single leaky integrate-to-threshold unit (LTU) node or more nodes. The node n_(i) equations are:

$V_{i} = {\sum\limits_{j}^{\;}{w_{ij}k_{j}}}$ n_(i) = ⊓(Vi − Th_(x))

where, Π is a Heaviside step function; w_(ij) is a coupling node unit (CNU) between node i and image component j (for example, grayscale value of a certain pixel j); k_(j) is an image component ‘j’ (for example, grayscale value of a certain pixel j); Th_(x) is a constant Threshold value, where x is ‘S’ for Signature and ‘RS’ for Robust Signature; and Vi is a Coupling Node Value.

The Threshold values Th_(x) are set differently for Signature generation and for Robust Signature generation. For example, for a certain distribution of Vi values (for the set of nodes), the thresholds for Signature (Th_(S)) and Robust Signature (Th_(RS)) are set apart, after optimization, according to at least one or more of the following criteria:

For: V _(i) >Th _(RS)

1−p(V>Th _(S))−−(1−ε)¹<<1   1.

i.e., given that l nodes (cores) constitute a Robust Signature of a certain image l, the probability that not all of these l nodes will belong to the Signature of same, but noisy image, Ĩ is sufficiently low (according to a system's specified accuracy).

p(V _(i) >Th _(RS))≈l/L   2.

i.e., approximately l out of the total L nodes can be found to generate a Robust Signature according to the above definition.

3: Both Robust Signature and Signature are Generated for Certain Frame i.

It should be understood that the generation of a signature is unidirectional, and typically yields lossless compression, where the characteristics of the compressed data are maintained but the uncompressed data cannot be reconstructed. Therefore, a signature can be used for the purpose of comparison to another signature without the need of comparison to the original data. The detailed description of the Signature generation can be found in U.S. Pat. Nos. 8,326,775 and 8,312,031, assigned to common assignee, that are hereby incorporated by reference for all the useful information they contain.

A Computational Core generation is a process of definition, selection, and tuning of the parameters of the cores for a certain realization in a specific system and application. The process is based on several design considerations, such as:

(a) The Cores should be designed so as to obtain maximal independence, i.e., the projection from a signal space should generate a maximal pair-wise distance between any two cores' projections into a high-dimensional space.

(b) The Cores should be optimally designed for the type of signals, i.e., the Cores should be maximally sensitive to the spatio-temporal structure of the injected signal, for example, and in particular, sensitive to local correlations in time and space. Thus, in some cases a core represents a dynamic system, such as in state space, phase space, edge of chaos, etc., which is uniquely used herein to exploit their maximal computational power.

(c) The Cores should be optimally designed with regard to invariance to a set of signal distortions, of interest in relevant applications. Detailed description of the Computational Core generation and the process for configuring such cores is discussed in more detail in U.S. Pat. No. 8,655,801 referenced above.

The various embodiments disclosed herein can be implemented as hardware, firmware, software, or any combination thereof. Moreover, the software is preferably implemented as an application program tangibly embodied on a program storage unit or computer readable medium consisting of parts, or of certain devices and/or a combination of devices. The application program may be uploaded to, and executed by, a machine comprising any suitable architecture. Preferably, the machine is implemented on a computer platform having hardware such as one or more central processing units (“CPUs”), a memory, and input/output interfaces. The computer platform may also include an operating system and microinstruction code. The various processes and functions described herein may be either part of the microinstruction code or part of the application program, or any combination thereof, which may be executed by a CPU, whether or not such a computer or processor is explicitly shown. In addition, various other peripheral units may be connected to the computer platform such as an additional data storage unit and a printing unit. Furthermore, a non-transitory computer readable medium is any computer readable medium except for a transitory propagating signal.

All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. 

What is claimed is:
 1. A method for searching for mobile applications using a multimedia content element, comprising: receiving an input search query including the multimedia content element; generating at least one signature for the at least one multimedia content element; generating a textual query using at least the one generated signature; querying at least one application distribution platform using the generated textual search query; analyzing search results returned responsive to the textual query to determine relevancy of mobile applications designated in the search results to the multimedia content element; and causing the display of mobile applications on a user device submitting the input search query.
 2. The method of claim 1, further comprising: creating an overlay on the at least one multimedia content element for receiving at least one search parameter representing an intent of the user, wherein the overlay is at least a search box.
 3. The method of claim 2, further comprising: receiving at least one of demographic information and location information related to a user submitting the input search query; and optimizing the generated textual query based on at least one of: the demographic information, the location information, and the at least one search parameter.
 4. The method of claim 2, wherein the at least one received multimedia content element includes one or more portions of the at least one multimedia content element, wherein a signature is generated for each of the one or more portions of the at least one multimedia content element.
 5. The method of claim 1, wherein generating the textual query further comprising: searching a query database for a textual query that matches the at least one generated signature, wherein the query database maintains mappings of signatures to textual queries, and wherein a plurality of signatures are mapped to a single textual query.
 6. The method of claim 5, further comprising: clustering the at least one generated signature; and searching the query database using the clustered signature.
 7. The method of claim 1, wherein generating the textual query further comprises: matching the at least one generated signature against a plurality of concepts; and using a metadata of at least one matching concept as the textual query.
 8. The method of claim 1, further comprising: determining a context of the multimedia content element respective of the at least one generated signature; and determining the textual query based on the determined context.
 9. The method of claim 1, wherein the search results include for each mobile application at least one icon, a plurality of screenshots, and a description of the mobile application.
 10. The method of claim 9, wherein analyzing the search results further comprises: generating at least one signature for the search results of each mobile application; matching the generated at one least signature for the search results to the at least one signature generated for the multimedia content element; and determining a respective mobile application to be relevant when the signatures match.
 11. The method of claim 1, wherein the at least one multimedia content element is at least one of: an image, graphics, a video stream, a video clip, an audio stream, an audio clip, a video frame, a photograph, images of signals, and portions thereof.
 12. A non-transitory computer readable medium having stored thereon instructions for causing one or more processing units to execute the method according to claim
 1. 13. A system for searching for mobile applications using a multimedia content element, comprising: a processor; and a memory coupled to the processor, the memory contains instructions that when executed by the processor cause the system to: receive an input search query including the multimedia content element; generate at least one signature for the at least one multimedia content element; generate a textual query using at least the one generated signature; query at least one application distribution platform using the generated textual search query; analyze search results returned responsive to the textual query to determine relevancy of mobile applications designated in the search results to the multimedia content element; and cause the display of mobile applications on a user device submitting the input search query.
 14. The system of claim 13, wherein the signature generator is communicatively connected to the processor.
 15. The system of claim 13, wherein the system is further configured to: create an overlay on the at least one multimedia content element for receiving at least one search parameter representing an intent of the user, wherein the overlay is at least a search box.
 16. The system of claim 13, wherein the system is further configured to: receive at least one of demographic information and location information related to a user submitting the input search query; and optimize the generated textual query based on at least one of: the demographic information, the location information, and the at least one search parameter.
 17. The system of claim 15, wherein the at least one received multimedia content element includes one or more portions of the at least one multimedia content element, wherein a signature is generated for each of the one or more portions of the at least one multimedia content element.
 18. The system of claim 13, wherein the system is further configured to: search a query database for a textual query that matches the at least one generated signature, wherein the query database maintains mappings of signatures to textual queries, and wherein a plurality of signatures are mapped to a single textual query.
 19. The system of claim 15, wherein the system is further configured to: cluster the at least one generated signature; and search the query database using the clustered signature.
 20. The system of claim 13, wherein the system is further configured to: match the at least one generated signature against a plurality of concepts; and use a metadata of at least one matching concept as the textual query.
 21. The system of claim 13, wherein the system is further configured to: determine a context of the multimedia content element respective of the at least one generated signature; and determine the textual query based on the determined context.
 22. The system of claim 13, wherein the search results include for each mobile application at least one icon, a plurality of screenshots, and a description of the mobile application.
 23. The system of claim 22, wherein the system is further configured to: generate at least one signature for the search results of each mobile application; match the generated at least one signature for the search results to the at least one signature generated for the multimedia content element; and determine a respective mobile application to be relevant when the signatures match.
 24. The system of claim 13, wherein the at least one multimedia content element is at least one of: an image, graphics, a video stream, a video clip, an audio stream, an audio clip, a video frame, a photograph, images of signals, and portions thereof. 